Routing system and method for synchronisation

摘要

There is described herein a method of synchronizing a border gateway protocol (BGP) routing system with peer BGP routing systems after failure of a primary processor of the BGP routing system. In such a system, the primary processor may utilize an original routing database for performing routing and may maintain a prefix table accessible to a backup routing processor listing prefixes of routes of the original routing database. The method may be performed by the backup processor upon detection of a failure of the primary routing processor. The method includes sending BGP route refresh messages to the BGP peer routing systems, the BGP route refresh messages requesting routes supported by the BGP peer routing systems, and receiving routes from the BGP peer routing systems in response to the BGP route refresh messages. A backup routing database may be generated from the routes received from the BGP peer routing systems. The backup processor may then compare the prefixes of routes in the backup routing database with prefixes in the prefix table. A BGP route withdraw message may be sent to any peer routing system for routes having prefixes listed in the prefix table but not identified in the backup routing database.